Tension device for sewing-machines



(No Model.) I

G. F. RUBY.

Tmmnm DEVICE FOR SEWING MACHINES. No 491,265. Patented Feb. 7, 1893.

WITNESSES l NETED GABRIEL F. RUBY, OF COLUMBUS, OHIO.

TENSION DEVlC E FOR SEWlNG-MACl-HNES.

SPECIFICATION forming part Of Letters Patent NQ. 491,265, dated February'7, 1893.

Application died March 23, 1892. Serial No. 426.118. (No model.)

the letters of reference marked thereon, which sion.

form part of this specification.

This invention relates to certain improvements in sewing machine tensiondevices.

lleretofore tension devices have in some instances been located on thearm of the machine and consisted of one or two plates each secured at anend and provided with an in terinediate clamping screw so that the free;end of the plate can be drawn down on the Also in some instances disk orwheel tension devices have been located on the face 1 plate of themachine and controlled by a The plate tension devices mentioned possesscertain radical disadvan-i tages encountered in practical use. The 11spring of the plate or plates gradually weak- 5 ens; the plate or platesbeing secured do not permit a sufticient play or movement to perthread.

spring and nut.

init tree passage of knots or uneven portions in the thread hence thethread wears and breakage is very apt totalre place. The wheel or disktension devices are also practically imperfect, and require that thethread entering the device he undertension, hence requiring asupplementary tension device. The thread ordinarily has to be wrappedseveral times around the wheel or between the disks,

A further object of my invention is to provide a plate tension devicepossessing, all the advantages of the disk 01- wheel devices and of theold plate devices mentioned and which will avoid the disadvantagesthereof by holding the thread away from the post and providing a tensionplate free to rock at either end or 'sidewise and yieldingly held inposition by a spring.

A further object of the invention is to reduce the number of parts andobviate the necessity of the supplementary tension device so that theportion of the thread entering the tension device need not be undertension and the outgoing portion only will be under ten- A furtherobject of the invention is to im- 1 prove certain details in thearrangement and construction or parts whereby a greatly improved andhighly efficient tension device will be produced.

The invention consists in certain novel features of construction and incombinations of parts more fully described hereinafter and particularlypointed out in the claims.

Referring to the accompanying drawings Figure 1, is an edge view of aface plate of a sewing machine showing the tension device in elevation.Fig. 2, is a front view of a face plate showing the tension device inedge elevation. Fig. 3, is a cross section through the face plate andtension device, enlarged. Fig. 4-, is a detail top plan of the tensionplate. Fig. 5, is a detail perspective view of the inner or base plateof the tension device.

In the drawings the reference letter a, indicates the face plate of asewing machine. As the present invention relates to the tension devicealone it is not deemed necessary to show the operative portions of asewing machine.

12, indicates a slotted threaded post rigid with and extending laterallyfrom the side or edge of the face plate.

0, indicates the base or inner stationary plate of the tension device.This plate is provided with the aperture cl, near its inner longitudinaledge for the post so that the plate does not project on that side of thepost. The portion of the plate projecting on the opposite side of thepost forms the hearing or clamping face 6, for the thread and over whichthe same passes. This plate is held stationary in any suitable manner orby suitable means. The plate is here shown provided with downwardlyprojecting longitudinal edge flanges f,f, which fit in correspondinggrooves in the face plate. However I do not wish to limit myself to anysuch specific construction or to any specific construction of inner baseor plate over which the thread travels. The edges of this plate arerounded to prevent wear on the thread and to permit easy insertion ofthe thread into the tension device.

g, indicates the tension or movable rocking plate of the tension deviceprovided with the approximately central aperture h, to receive thecentral post. A bridge or cross bar i, extends across this aperture andfits loosely in the slot of the post so that the plate can freely movelongitudinally of the post or can be removed therefromi When a threadreleasing device (not here shown) is employed a rod extendslongitudinally within the post and engages said bridge so that when therod is forced in by suitable means the tension plate will be raised fromthe inner base. The tension plate can also be provided with the flan gedor turned down endj, to engage the corner of the face plate and hold thetension plate against turning.

It should be observed that the inner longitudinal edge of the tensionplate projects beyond the corresponding edge of the base 0, so that aspace is left between said tension plate and the face of the face plateof the machine. At the lower end of said space below the end of the base0, the tension plate is provided with the thread eye 70, and a slotthrough the inner edge of the plate thereto, so that the thread can beeasily inserted into the eye. A corresponding thread eye I, is formeddirectly across the plate near the outer edge of the tension plate witha slot to the outer edge of the plate. The guide fingers m, formed bysaid slots are turned out to assist in inserting the thread in saidslots.

The thread eye 1, is located at one end (lower) of the clamping orengaging portions of the base 0, and tension plate g, and a thread eyea, is formed in the tension plate at its other end, so that the eyes Z,and n, are located at the opposite ends of the clamping or engagingportions of the base and tension plates. This thread eye it, is alsoprovided with an inserting slot extending through the upper end edge ofthe tension plate.

0,indicates a thumb or adjusting nut on the outer end of the said post,having a preferably flat inner end.

19, indicates a volute spring having its large end bearing and restingon the tension plate around the post and its opposite end bearingagainst said nut. One end of the spring is bent across the open centerof the spring to enter the slot of the post and hold the spring againstturning with said nut. I do not Wish to limit myself to any particularform or construction of spring but prefer the form here shown.

It should be observed that the aperture 7L, and the bridge 2' are soproportioned in relation to the post that the tension plate is free torock sidewise or at either end, and that the large end and extendedbearing of the spring on said plate assists these movements. It shouldalso be observed that a line drawn between the thread eyes Z, and n,would be located a distance to the outside of the post, hence the threadguided by said eyes will be held away from the post.

In practice the thread extends down the face plate from open loop, eyeor guide q, (the thread is lettered 0",) beneath the inner side or edgeof the tension plate through eye 7c, transversely across the outside ofthe lower end of the tension plate, through eye Z, and thenlongitudinally of the base and tension plate and between the clampingfaces thereof and through eye a, and around to the take up of themachine not here shown. The tension is applied to the thread between theeyes Z, and 7t, and longitudinally of thetension plate and to one sideof the post so that when knots or uneven portions of the thread enterthe tension device, the lower end of the tension plate can give orspring out, and as the enlarged portion passes up the plate can givesidewise and then the upper end of the plate can give out. The plate canthus give at all points and relieve itself instantly with a minimumamount of wear on the thread. The plate is free to rock in alldirections, and yet can be easily and quickly adjusted to Vary thetension by means of the nut and spring, also the rocking or automaticadjustment of the tension plate will permit different sizes of threadswithout turning the thumb nut. It should also be observed that by reasonof the peculiar construction no supplementary tension device for theingoing portion of the thread is required, but the thread merely passesthrough the guide g, which exerts no tension thereon.

Great advantages are attained by combining the rocking or unsecuredtension plate with the spring yieldingly holding the same in position,as it permits the machine to sew a regular accurate stitch,whereas inthe ordinary plate tensions where the spring plate is held down by ascrew the movement of the thread was retarded when an unevenness orroughness in the thread was passing under the spring plate as suchunevenness had to be crushed down to permit its passage thereby drawingback on the thread. In my construction the thread moves under thetension plate ata constant and regular rate of speed without retardationby such plate as the plate freely rocks and permits rough or enlargedportions of the thread to slide through. Furthermore as my plate is notrequired to spring, but has a spring holding it in place there is noweakening as is the case where the tension plate itself has to springand is formed of elastic material.

The extreme simplicity and great utility of this invention are obviouswithout further explanation.

It is evident that various slight changes might be made in the form,construction and arrangement of the parts described without departingfrom the spirit and scope of my invention, hence I do not wish to limitmyself to exactly what is here shown and described, but

Having fully described my invention what I claim and desire to secure byLetters Patent of the United States is:

i. In a tension device, the combination of a post, a support therefor, abase plate eccentrically mounted on the post, a tension plate looselymounted on the post and bearing on said base on one side of the post,and provided with the thread eyes to hold the thread away from the postand longitudinally of and between the base and tension plate, and aspring yieldingly holding the tension plate in position.

2. In a tension device, the combination of a support, a base, a post, alaterally and longitudinally tilting tension plate having an enlargedaperture between its ends through which said post passes,thelongitudinal clamping faces of. the plate and base located to one sideof and parallel with the longitudinal axis on which the plate rocks, thespring on the post holding the plate to the base, and meanssubstantially as described to hold the thread between said clampingfaces and away from the post, substantially as described.

3. The tension device coinprisingasupport, a base, a post, a tensionplate having an aperture between its ends and side edges loosely fittedon the post to permit swing on longitudinal and transverse axes, oneedge of said plate extending beyond the corresponding edge of the base,a spring on the post bearing on the plate, one end of the plate havingtwo thread eyes, respectively, on opposite sides of the longitudinalaxis of the plate and one thread eye at the other end of the plate onone side of the longitudinal axis thereof substantially as described.

In testimony that I claim the foregoing as my own I alfix my signaturein presence of two Witnesses.

GABRlEL F. RUBY.

Witnesses:

O. M. "WERLE, HUBERT E. PECK,

